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Instrument for fine-mechanical or surgical applications

Instrument for fine-mechanical or surgical applications description/claims

The invention relates to an instrument for high-precision or surgical applications of a minimally invasive nature, comprising a distally positioned directable head, a rigid, flexible, or semi-flexible shaft upon which the head is positioned, and a proximal end equipped for operating the head. This proximal end may be provided with, or example, a handgrip or a control (possibly motor-powered). In the latter case, this may also entail a computerised control. The high-precision applications include, for example, the inspection and repair of motors, machines, radiators or tubular systems.

Such an instrument is known for medical applications from, among others, the international patent application PCT/NL01/00552, published under no. WO 02/13682.

From this publication an endoscope is known, embodied with a distally positioned camera, fitted on an endoscope shaft, wherein proximally positioned means are provided for operating the camera. To realise the coupling or the operating means and the camera, use is made of a spring, which is comprised of a chain of in themselves closed, flexible elements wherein the elements or each pair of two adjacent elements as comprised in this chain are only partially connected with each other. Through these mutually connected elements traction wires are threaded through feed-through openings that are provided in the elements.

The known construction has several drawbacks. These drawbacks concern the fact that there is a limit to how small the elements forming the spring can be while still keeping the spring at a desirably low cost price. Another drawback is that when the camera is set at an angle to the shaft, the four traction wires used in the known construction establish referred positions.

An object of the invention is to eliminate these problems and to allow the medical instrument to be constructed at low costs.

Corresponding to the preamble of claim 1, an instrument of the kind explained above is known from US-A-2002/0177750, wherein a ring of cables comprising longitudinally extending cables connects to the head, which cables are fixedly secured in the radial direction. A disadvantage of this instrument is, however, that the cables are fed through guide-sleeves provided in the longitudinal direction of the cables and attached to an externally extending leaf spring. This construction is complex and expensive.

The instrument according to the invention is characterized in that each cable of the ring of cables is disposed such that at least a part of both sides is in direct contact with another cable of the ring of cables.

This instrument lends itself especially for surgical applications, as will become apparent From the following explanation. Of course, high-precision applications are equally well possible, and may be derived without inventive effort from the explanation given hereinbelow. It should be noted that other longitudinally extending elements, with which a closed ring can be formed, also fall within the scope of the term “cable” used in the invention. This relates, for example, to a ring of (hollow) tubes, or glass fibres to be mentioned hereinbelow. Similarly, it is not necessary for all of the cables to have the same dimensions. For example, cables having a completely round cross-section may be disposed next to cables having a banana-shaped cross-section.

The instrument according to the invention can be manufactured at exceptionally low costs since the cables may be thin steel cables of the kind normally available on the market. Such steel cables are available with a diameter of, for example, 0.2 mm. This means that if a central channel de-limiting the ring of cables has a diameter of 0.2 mm, it is possible to manufacture a ring of cables having a minimum diameter of 0.6 mm. It is thus possible to realise a shaft diameter having a diameter of approximately 1 mm.

An essential aspect or the invention Is that in the radial and tangential direction, the cables of the ring of cables are fixedly secured. Preferably, the cables comprising the ring of cables are over their whole length in direct contact with neighbouring cables. This enables the cables of the ring of cables to absorb a pulling force as well as a pushing force, allowing the ring of cables to be used for the mechanical coupling of the head to a handgrip.

An important advantage of the instrument according to the invention is further that the same is without preferred positions with respect to the movement of the head in relation to the shaft.

For the mechanical coupling of the head to the handgrip any cable from the ring of cables may be employed. In a preferred embodiment, however, the instrument according to the invention is characterized in that the ends of at least some of the cables of the ring of cables possess a fastening to the head and to the proximal end. In this way the fastening can be constructed in a simple and consequently cheap manner, for example, by means of soldered connections or by using bolts provided in an endplate wherein the ends of the cables having a pulling function can be received.

An embodiment that is preferred when all of the cables provide the mechanical coupling for the head to the handgrip, is characterized in that the fastening is embodied as an interior ring and an exterior ring, which together delimit a slot for clampingly receiving the cables. This construction can also be used if only some of the cables of the ring or cables are received in the slot.

A simple and inexpensive embodiment of, the instrument according to the invention for the fixedly securing the ring of cables is characterized in that the ring of cables is enclosed by an exterior spring lying against the cables of the ring of cables.

It is also possible for the ring of cables to be provided at its exterior side with a construction element selected from the group comprising glass fibres, cables, power cables, power cables surrounded by glass fibres, an optionally torsion-stiff tube or tubes, optionally with lateral scoring and optionally stranded, a bellows, a stent and a spring as specified in WO 02/13682.

For the internal retention of the ring of cables numerous technical possibilities can be used. For example, a simple and effective possibility is to be found in the embodiment wherein the ring of cables is provided at its interior side with an interior spring lying against the cables of the ring of cables.

It is also possible for the ring of cables to be provided at its interior side with a construction element that is selected from the group comprising a bundle of glass fibres, a cable, power cables, a power cable surrounded by a ring of glass fibres, an optionally torsion-stiff tube or tubes, optionally with lateral scoring and optionally stranded, bellows, a stent and a spring as specified in WO 02/13682.

It is also conceivable that the construction element selected from this group is used in combination with an internal spring lying against the cables of the ring of cables. If such an internal spring is not used, the selected construction element itself must lie against the cables of the ring of cables.

If the construction element is a cable, it is advantageous that on the head of the instrument a grab jaw, scissors or clipping tongs be mounted and the cable be embodied as control cable therefor. This is especially useful for medical applications.

However, if the construction element comprises a power cable, it is advantageous for the instrument to be embodied with a camera mounted on the head, wherein the power cable serves for the power supply of said camera and/or for transporting image data obtained with the camera. Of course, it is also possible to use several power cables having separate functions. In addition, the power cable or power cables may serve for feeding a light source, such as an LED or the like. Glass fibres are also useful as light conductors, while they are at the same time able to serve as traction rope.

The instrument proposed in accordance with the invention, is preferably selected from the group comprising laparoscope, thoracoscope, colonoscope, gastroscoie, bronchoscope, endoscope, catheter, surgical drill, uretheroscope, laryngoscope, cystoscope, guidable endoscope, guidable drill, gripping tongs, clipping tongs, scissors, coagulation hook, and generally instruments for ear, nose and throat surgery, eye surgery, neurosurgery and brain surgery.

• Provisional Patent
• Utility Patent

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